The present invention relates to aqueous adhesion assistant or binder dispersions for use in the production of composite bodies by vulcanizing a vulcanizable rubber composition on a substrate which is stable under vulcanizing conditions, and the method of bonding rubbers to solid substrates.
Adhesion assistants or binders for the bonding of rubber by vulcanization onto substrates which are stable under vulcanization conditions, such as metals or also textiles, plastics or elastomers, have long been known. The binders suitable for universal bonding of elastomeric materials to metallic substrates at elevated temperatures normally contain polymeric film-formers, bonding aids, fillers and additives as well as organic solvents. U.S. Pat. No. 3,878,134, issued Apr. 15, 1975 to Ozelli et al, describes one such composition. A preferred group are products which contain halogenated or chlorosulfonated rubbers as film formers, polyfunctional isocyanates and/or organosilanes, as well as aromatic poly-nitroso-compounds as bonding aids, carbon black, silicic acid, basic lead phosphite and/or zinc oxide as fillers and additives, and aromatic and/or halogenated hydrocarbons as solvents.
Also known are binders which contain aqueous dispersions or solutions of specific carboxyl groupcontaining rubbers as main components, in combination with the usual solvents, as well as the combination of aqueous polymer dispersions with resorcinol/formaldehyde resins.
While the conventional adhesion assistants or binders have the disadvantages connected with the use of organic solvents with respect to toxicity, combustibility, economic efficiency, etc., the binders based on aqueous dispersions or solutions known until now actually do not show these disadvantages. However, what hinders a broader use of these systems is their lack of universality with respect to the elastomeric substrates to be bonded.